The present invention relates to dynamoelectric machines and, more particularly, to replacement motor kits and parts thereof; such motors being marketable to provide replacement motors interchangeable with motors that have failed in the field.
Different types of equipment used in homes or elsewhere are equipped with electric motors. Malfunctions or failure of the motor in such equipment may impair or stop the use of the equipment until the malfunctioning motor is repaired or replaced. When motor malfunction or failure occurs, the owner or operator of the equipment is at least inconvenienced and, to an ever increasing extent, the cost of repairing or replacing a motor within such equipment may be disproportionate as compared to the original manufacturing cost of the motor.
For example, in the case of domestic household refrigerators which are provided with evaporator fans, the fan motors that are used to circulate air across the evaporator coils typically represent a very small fraction of the total cost of manufacturing the refrigerator. This is particularly the case when such motors have been manufactured on a large volume production basis. Motors of this type may be as described in Rutledge et al U.S. Pat. No. 3,359,628.
Motors constructed using this approach generally are not repairable if bearing failure occurs, and the entire motor must be replaced if bearing failure occurs in the field. In addition, even if "repairable" motors were used for these types of applications, it would be the generally more economical practice to replace rather than attempt to repair them in the field.
Even though extensive efforts are made to provide motors having a more than sufficient expected service life, inadvertent failures or malfunctions of small fan motors nonetheless occur. Because of this, it has become a general practice in the industry for service shops to carry an inventory of motors that are then used to replace motors in the field. However, due to an increasing number of manufacturing sources of appliances and motors, it is necessary for service shops to carry an ever increasing inventory of different motors. Most of these motors are not interchangeable, one with another, because of (among other things) differences in shaft length, differences in shaft diameter, and different mounting features or mounting adapters.
The net effect of this situation upon the ultimate equipment or appliance user is that the cost of replacing a relatively small component in a given apparatus has continued to become increasingly great. While the reasons for such increased expense are explainable, such explanations provide little solace to the user. Different approaches have been considered and attempted to at least partly remedy the problems just discussed, but such approaches have not been completely satisfactory. For example, replacement motors with extra long shafts have been modified by sawing off part of the shaft. This however, can result in bending the shaft-particularly in the case of small motors having small shaft diameters. A bent shaft of course may cause vibration and noise during operation and also may contribute to premature failure of the bearings in the replacement motor.
We have concluded that it would be desirable to provide a motor arrangement whereby a motor manufacturer can provide a single unit or package to wholesalers or service repair stations which can be used to replace numerous different motors in the field that are not directly interchangeable one with another. By doing this, we believe that further savings can be realized since it would become feasible to manufacture replacement motor arrangements on a continuing production basis.